Abstract: An irrigation system (10) including a microcomputer (12) and a delay apparatus (16). A preferred delay apparatus (16) includes a power detection circuit (20) capable of detecting short-term disturbances in the power being supplied to the microcomputer (12). Delay apparatus (16) also preferably includes a timer circuit (22) which, when power detection circuit (20) detects a short-term disturbance, acts with a switch (24) to interrupt the AC power to the microcomputer (12) for a preselected period of time. The timer circuit (22) can produce a delay of approximately five or six seconds which is suitable for causing microcomputer (12) to restart or reboot, rather than lock-up or otherwise suffer a corruption of data were the momentary power disturbance to reach microcomputer (12).

Abstract: A high efficiency integrated power converter adapted for direct connection to line voltage and having on chip protection from overcurrent may be implemented utilizing a GTO-SCR as the switch element in a switching power converter such that the converter requires no external transformer or inductor based voltage reducing circuitry. The input voltage may vary over a wide dynamic range without deterioration in circuit performance due to the extremely high anode to cathode breakdown voltage of the switching element and further due to the on chip protection from excess current flow through the switching element.

Abstract: An electronic power supply that converts alternating current to a regulated DC voltage with high efficiency is accomplished by a switch that connects the input AC power source directly to the DC output filter capacitor. This occurs when the input voltage equals the output voltage, and the output voltage is less than the set value.This power supply can be used with low impedance AC power sources capable of providing high surge currents such as commercial utility lines.

Abstract: A switching arrangement for full-wave power control comprising a triac (2), the control electrode of which is preceded by a trigger diode, the control voltage being taken from an RC section having at least one potentiometer (9), which effects a phase shift in the firing time as a function of the position of the potentiometer (9), is improved by the RC section (9, 10) being connected to a constant voltage source. This consists of two Z diodes (6) which are connectd in opposition and which are advantageously bridged by means of an adjustable voltage divider (7, 8), in such a manner that the RC section (9, 10) is connected to an adjustable part voltage. Instead of bridging the triac (2) for full drive, as usual, the trigger diode (11) is connected to a special bias resistor by means of a switch (13). According to a preferred embodiment, the resistors of the switching arrangement consists of a low-temperature thick-film paste printed on a hard paper board (see drawing relating to this).

Abstract: A phase controlled regulator for selectively connecting a load to an AC source voltage such that substantially constant power is delivered to the load despite fluctuations in the magnitude of the source voltage is comprised of a circuit for detecting the zero crossings of the AC source voltage. A circuit produces a reference signal representative of a periodically increasing value in response to the zero crossings of the AC source voltage. A sensor produces a first signal representative of the instantaneous value of the AC source voltage. A comparator compares the reference signal with the first signal and produces an output signal when a predetermined relationship exists therebetween. A switch is responsive to the output signal for selectively connecting the load to the AC source voltage.

Abstract: An electromagnetic induction heating cooker compatible with both 100 V and 220 V inputs. A parallel circuit of a 100 V select switch and a transistor is connected between an output terminal of a bridge diode and a choke coil. The output terminals of the bridge diode and the choke coil are respectively connected to a pair of resistors in series whose values are set so that the same voltages are applied to a non-inverting and inverting input terminals of a comparator when the ratio of the output voltage of the bridge diode to that of the choke coil is 2.2:1. An oscillator, a drive, and a 220 V select switch are connected in series between an output of the comparator and the base of the transistor.

Abstract: A circuit for controlling the initiation and operation of a phase control circuit employed in voltage regulation to a load such as dimming lights. The circuit uses a power semi-conductor which is triggered by a "walk-in" circuit. The "walk-in" circuit includes a regulator diode across a diode bridge which stabilizes the output of the load, such as a level of lighting.

Abstract: An improved switching arrangement for a direct coupled switching power supply is provided by utilizing a gate turn off SCR as the primary switching element and a second SCR as the turn-off control such that upon detection of any of a fully charged storage element, an excessive current through the gate turn off SCR, or an insufficient input voltage, the switch is turned off.

Abstract: Disclosed is a touch control lamp system, including a touch control dimmer switch adapted to be plugged into a standard electrical household outlet, and a lamp having a male electrical plug adapted to plug into the touch control switch. When the plug from the lamp is plugged into the touch control switch, a touch control wire in the power cord of the lamp connects a conductive portion of the lamp to the touch control circuitry in the touch control switch, so that the lamp may be controlled by touching the conductive portion of the lamp. Moreover, a conventional lamp may be plugged into the touch control switch, which may be controlled by a touch control wire separately connected to the touch control switch.

Abstract: A DC power source is capable of automatically adapting to either a 120 or 240 VAC input and of providing a single regulated output range for either of the AC voltage levels provided thereto. The power source detects the AC input voltage and automatically doubles the lower voltage while allowing the higher rectified voltage to pass through. The power source includes an electronic switching arrangement responsive to the input voltage level for automatically doubling the lower AC input voltage when detected as well as timing circuitry to allow for transitory fluctuations in the input voltage level while maintaining a level DC output voltage.

Abstract: An electric power unit capable of operating from different AC input power source voltages in which changes in the AC input voltage are compensated for automatically and rapidly. The power unit includes a rectifier circuit having both a voltage-multiplying rectification function and a non-voltage-multiplying rectification function. A switching circuit is provided for selecting as the operating rectification function one of the voltage-multiplying rectification function and the non-voltage-multiplying rectification function. A switching control circuit, operating with the AC input to the rectifier circuit as a reference potential, controls the switching circuit according to the value of the AC input voltage. An auxiliary power source establishes a voltage for powering the switching control circuit before the operation of the switching control circuit to select the rectification function is effected.

Abstract: This patent presents a touch-responsive switch which incrementally varies AC voltage supplied to an electrical apparatus. The invention includes digital circuitry which compares a control pulse train with a touch affected pulse train to create a switching pulse. The switching pulse is synchronous with the line frequency and controls truncating of individual cycles of line power to regulate voltage applied to an appliance as a function of the number of times a touch plate has been touched. The switching pulse also provides on/off switching as one of the available incremental steps. The circuit components are incorporated in an interface assembly which connects the appliance receptacle to a source of AC voltage.

Abstract: A low-pressure mercury vapor discharge lamp comprises a tubular bulb having an inside diameter of from 22 mm to 35 mm, an electrode-to-electrode distance of from 400 mm to 1,200 mm, and an inner surface coated with a phosphor. A rare gas including Kr and a mercury vapor source are sealed in the bulb, which is energized by an igniting device having a high-frequency power supply connected to a DC power supply for generating a substantially sinusoidal high-frequency output voltage, and a quiescent period generator connected to the high-frequency power supply and including a switch 17 turned on and off at least once during each half cycle to provide a quiescent period and thereby produce a substantially square wave high-frequency output voltage having rise and fall times of 2 .mu.s or less.

Abstract: A phase control ballast in which a reactor and a triac are connected in series with an hid discharge lamp across an ac voltage source. A supra-linear converter connected to a rectifier-filter provides a reference voltage which is a supra-linear function of the source voltage. A ramp generator provides a ramp voltage climbing at a constant rate. At the instant when the ramp voltage exceeds the level of the reference voltage, a comparator circuit provides a signal to the gate of the triac which turns it on. A triac state detector responds to the turning on of the triac in either polarity by dropping the ramp voltage to zero and holding it at zero until the triac turns itself off.

Abstract: The power drawn by a load (R.sub.L) from an A.C. network is controlled by an operational amplifier (OP1) and a power transistor (TR2). The operational amplifier makes the transistor leading when the voltage of its inverting input which is derived from said network, is lower than a reference voltage supplied to its non-inverting input. The pulses through the load take a form corresponding to the first and last parts of a sinusoidal half-wave. Their time lengths are shortened according as the voltage of the feeding network increases, and vice versa. FIG. 1.

Abstract: A control circuit for supplying a relatively constant operating voltage to an electrical load over a relatively wide range of supply line voltages, including an electronic switch connected in series with the electrical load and having a control lead, a reference voltage generating element, and a comparator for receiving the reference voltage and a voltage representative of the actual voltage applied to the electrical load and for generating and electrical signal which is applied to the control lead of the electronic switch.

Abstract: A DC power source apparatus is provided including a current regulator having an electronic contactor, a transformer having a primary winding and a secondary winding. A series circuit of the primary winding and the current regulator is adapted for connection to an AC power source. The AC power source apparatus also includes a rectifier connected to the secondary winding of the transformer, output terminals of the rectifier being adapted to supply DC current to a DC load having an inductance. The AC power source apparatus further includes a simulator connected to detect an AC current flowing through the series circuit for simulating the DC current flowing through the DC load based on the detected AC current and a simulated time constant of the DC load to produce a simulated signal, and a controller connected to receive the simulated signal for comparing the simulated signal with a predetermined current reference to produce a phase control signal based on a comparison result.

Abstract: This apparatus can limit the power by limiting the duty cycle of current carried by a pair of lines. These lines intermittently conduct electrical power. A clock can provide a periodic timing signal. This clock is resettable to change the phasing of the timing signal. A switch serially coupled to at least one of the lines can periodically interrupt current of the lines with a period proportional to the period of the periodic timing signal. A resetter coupled to at least one of the lines can reset the clock in response to the average magnitude of voltage across the lines increasing by a predetermined extent.

Abstract: This apparatus can apply electrical power to a supply terminal from a pair of lines having a variable current and voltage. The apparatus has a voltage tapper and a series device. The voltage tapper is coupled to the lines and to the terminal for applying to the latter power drawn from the lines when their voltage difference exceeds a predetermined value. The series device is serially coupled into a given one of the lines for producing a voltage drop. The series device is coupled to the supply terminal for supplying power thereto as a predetermined function of the voltage drop of the series device.

Abstract: The varying impedance of a solar generator is matched with the fixed or varying impedance of a load driven therefrom by comparing the generator voltage with a reference voltage and producing a difference signal indicative of the difference, if any, in the voltages, repetitively switching "on" and "off" the current flow from the generator to the load according to the voltage difference so as to maintain the generator voltage at a substantially constant level. Energy generated during periods when current is not supplied to the load is stored for supply during periods when current is switched on to the load.

Abstract: A synchronization voltage is formed as the product of the output voltage of a phase-locked loop and the mean value of the magnitude of the network voltage. The synchronization voltage is compared with the network voltage. A first control signal is formed when both voltages are the same. A reversing switch, in a first switching state, conducts the network voltage and, in a second switching state, conducts the synchronization voltage to a reference frequency-input of the phase-locked loop. A second control signal is formed when the phase-locked loop locks or latches with the thereto inputted reference frequency. The reversing switch is controlled by both control signals such that upon absence of the first control signal and the simultaneous presence of the second control signal there is attained the second switching state and otherwise the first switching state.

Abstract: In a pump drive circuit, a power source voltage signal supplied to the pump is phase-controlled by a triac connected between the pump and the power source. The period of triggering the triac is determined by a time constant circuit of a UJT, a capacitor and a resistor circuit. The power source voltage signal has its frequency determined by a frequency discrimination circuit. The resistance value of the resistor circuit is selected in accordance with the result of the discrimination. Accordingly, the pump is applied with a voltage signal the phase of which is controlled in accordance with the power source frequency, and is thus driven to maintain a predetermined output.

Abstract: A phase-detector (16, 18, 20) is provided for use in a power factor controller for a three-phase induction motor. The power factor controller includes switching thyristors (10, 12 14) for each motor phase winding and the phase detector for each phase includes an operational amplifier (36) which senses the current phase angle for that phase by sensing the voltage across the phase thyristor. Common mode rejection is achieved by providing positive feedback between the input and output of the voltage sensing operational amplifier.

Abstract: An inexpensive power supply for an electconic control system or the like which is capable of converting a wide range of applied AC voltages into a regulated output voltage. A thyristor is coupled in series with an input terminal and a threshold device, such as a Zener diode, placed across the input terminals and paralleled by an RC circuit coupled to the thyrisor gate. Another capacitor is coupled to the thyristor cathode. A ramp-like voltage impressed on the thyristor gate effects triggering at a phase angle which varies in accordance with output voltage. The electronic control system outputs a uniform train of pulses which serve to disable a circuit interrupter. Termination or disruption of the pulse train causes the interrupter to open the protected circuit.

Abstract: A circuit arrangement for the compensation of voltage variations of the electrical AC polyphase power line for an AC-DC converter (3).The invention comprises a first circuit (5) for determining the voltage variations at the input of each trigger rectifier (Th.sub.1, Th.sub.2, Th.sub.3) of a converter (3) and a compensating circuit (6) for compensating the firing angle of each trigger rectifier. The compensating circuit (6) is connected to an output (7) of the first circuit (5) for determining the variations in the input voltage of each rectifier. Outputs of the compensating circuit (6) are connected to control inputs of the pulse generator (4) for controlling the firing angle of each rectifier so as to adjust the period of the firing pulses of each trigger rectifier (Th.sub.1, Th.sub.2, Th.sub.3). The invention is particularly applicable to electrical DC power supplys for data processing systems.

Abstract: A voltage or current balancing control for supplying a balanced three-phase alternating current supply to an electrical three-phase load. Three controllable full wave semiconductor gates respectively feed one phase of a three-phase alternating current supply to the electrical load. The semiconductor gates are adapted to controllably adjust the voltage or current of a phase of the supply in accordance with a gate control signal to be applied thereto. A comparator circuit is connected to receive the three-phase alternating current supply and is adapted to compare either the voltage or current characteristics, or both (power) of each phase to determine an unbalanced condition therebetween which is analyzed by an analog or digital computer, which accordingly supplies gate control signals to the semiconductor gates respectively to independently control them in accordance with the unbalanced condition to adjust the voltage and/or current of all three phases of the supply to an equal or balanced condition.

Abstract: An induction heating system (40) is provided and includes a plurality of induction heating coils (118). Touch control pads (50, 52, 70, 72) are provided together with circuitry (80) for generating energization control signals. Circuitry (112, 116) is provided for electrically energizing the induction heating coils (118). An electronic digital processor (82) is responsive to the energization control signals for generating energization signals for actuating and controlling the energization circuitry (112, 116) to thereby vary the energization of the plurality of induction heating coils (118).

Abstract: A circuit is provided for regulating the application of power to a load which is relatively insensitive to rapid power fluctuation of the type exemplified by typical AC line sources. In one embodiment, an AC line source is applied at a controlled rate to a tungsten lamp whose operation is controlled by a transistor switching network. The transistor operation, in turn, is controlled by comparing a portion of the rectified signal with a signal proportional to the light output of the lamp.

Abstract: A power circuit for a precipitator utilizes a pair of silicon controlled rectifiers (SCR's) which are triggered by detecting the zero crossover of a power signal. The power transmitted through the SCR's is determined by the time period from the detection of the zero crossover to the generation of the trigger signal. Power signals are typically subject to noise which interferes with the detection of the zero crossover. Filters are provided for reducing the noise interference but function without altering the phase relation of the zero crossover of the filtered signal in respect to the unfiltered power signal. A pulse train of higher frequency than the power signal is generated to provide a plurality of triggering pulses for the SCR. Further, phase control signals are generated for each SCR to prevent the generation of trigger pulses when the SCR's are reverse biased.

Abstract: An apparatus and method for regulating alternating current electrical power conducted to an electrical load wherein a gate control bidirectional semiconductor switch is controlled by a sensing circuit which includes feedback elements for responding to fluctuation in voltage supplied from a power source and in current demanded by the load for maintaining a predetermined average voltage delivered through the apparatus and in accordance with the method.

Abstract: A voltage reducing circuit device for reducing the RMS value of an incoming AC voltage is disclosed herein. This device is especially suitable for reducing line voltage applied to a load requiring lower voltage. In a preferred embodiment, the device is one which allows a domestic made 115 VAC small heating apparatus, such as a hair dryer, to be used in foreign countries where the 230 VAC service is available. In any case, the device is one which is relatively insensitive to fluctuations in line voltage and to changes in frequency.

Abstract: A closed loop phase control circuit. The circuit senses the temperature of a load circuit. It also senses the line voltage on each line of a multi-phase system. The sensed line voltage is full-wave rectified. Comparators for each phase compare an input signal indicative of the temperature of the load circuit with the full-wave rectified line voltage in the corresponding phase and develops an output signal when the full-wave rectified line voltage exceeds the input signal indicative of the temperature of the load circuit. Ultimately, triacs, which are in series with the load for each phase, respond to the existence of an output signal from the corresponding comparators and to a pulse from a timer and conduct in response thereto. When a triac conducts, line current is delivered to its corresponding load resistance. In this way, the time for delivery of line current (and line voltage) to the load resistance varies in accordance with the temperature of the load.

Abstract: A controller having dedicated fuser circuitry and a processor for controlling the fuser heating element. The dedicated fuser circuitry interconnects an input voltage source to the processor through a low voltage power supply to provide a reference signal and a sample DC voltage signal representative of the input voltage source. The processor provides a digital signal to activate a triac connected to the fuser heating element. The triac, selectively gates the input voltage source across the heating element. A plurality of ranges of digital signals and a plurality of corresponding triac activation rates are provided for variations in input voltage. A digital signal related to a particular value of the input voltage source lies within one of the plurality of ranges determining the particular activation rate of the triac.

Abstract: Current inrush limiting apparatus is disclosed including a power supply circuit (32) which regulates the transmission of power from a source (12) to a load (14). A soft start control (36) controls the power supply to prevent excessive current inrush to the load by causing it to apply power to the load gradually when the power first comes on. A dropout timer (38) monitors the power signal and rapidly resets the soft start control circuit if a power dropout exceeds a predetermined minimum duration. This ensures that excessive current inrush also does not occur following brief power dropouts.

Abstract: A phase control device for use in a phase control circuit, which forms a comparison signal synchronous with an a.c. power source, then compares this comparison signal directly with a preset phase control angle signal, and controls a phase control element provided in the a.c. phase control circuit by the compared output.

Abstract: A phase fired controller is provided for eliminating large shifts in the firing angle due to line voltage variations. Another advantage of the controller is that variations resulting from parts tolerances are reduced substantially. This is accomplished by controlling the output of a capacitor that supplies a voltage to a comparator. The system has particular utility when used as a dimmer controller of an electrostatic copier.

Abstract: An automatic voltage compensation control for a microprocessor controlled resistance welder system includes a digital voltmeter for measuring the line voltage cycle by cycle and associated circuitry to compensate the welding current in response to the measured line voltage in a manner which tends to hold the welding current constant and independent of line voltage variations. The digital voltmeter consists of a voltage-to-frequency converter coupled to a counter. The output of the voltage-to-frequency converter which is proportional to the line voltage is accumulated for the period of one cycle of the line frequency. This produces in the counter at the end of each measurement interval, a number of counts proportional to the average line voltage. The microprocessor using the count obtained adjusts the welding current by altering the timing of the firing points of the SCR contactors used to control the welding current.